I concur with this. The bullets that are used in the 17 rimfires are extremely explosive bullets and that is compounded by their excessive velocities. I don't think they will penetrate far enough into a coyote on a regular basis to facilitate one shot kills. They are excellent on tiny critters like squirrels and rabbits. However if you enjoy eating the meat from the tiny critters, you need to get really good at head shots because they literally explode on impact. I have used both the .17 mach 2 and .17 HMR for squirrels and if you miss a bit and hit them in the body, there is no meat left to eat. It pretty much just splits them in two. I like the .17's a lot but I do not use them on coyotes.